One problem with most beverages, ready-to-eat foods, and other products that require heating or cooling is that they are not ready for consumption straight out of the container (e.g. they are not heated or cooled). Rather, they must be heated or cooled by external means. In the context of heated foods, although instant teas or soups can be heated by adding hot or boiling water to the container, this assumes that the user has access to a supply of hot water. Many times this is simply not true. For example, the user may be outdoors or otherwise without access to microwaves, stoves, electricity, fuel or other external power means. Further, in emergency situations, instant access to heated beverages, food or other products may be vital to survival such as delivery of certain drugs, wax, cosmetics, massage oils, and commercial glues such as resins and epoxies.
To solve the various problems outlined above, many solutions have been proposed. For example, temperature changing hot beverages and soups have been provided in which the outer container includes an inner contents chamber (to hold the beverage, soup or other contents to be heated), a quick-lime chamber, and a water chamber. The user causes the water chamber to communicate with the quick lime chamber, and the combination of water and quick-lime gives rise to a fast exothermic reaction (for example, see U.S. Pat. No. 7,117,684 to Scudder et al.). While these known hot containers provide the user with heated contents, they have drawbacks. First, the quick-lime and water reaction completes very quickly so that although the contents are initially hot, they cool down as soon as the exothermic reaction completes, which may be only a few minutes. Second, the quick-lime exothermic reaction is extremely hot and can lead to contents that are dangerously hot thus requiring a container that can withstand extremely high temperatures. Finally, the quick-lime and water combination creates a hot slurry that can easily leak out of the container and cause burns, unless a complicated one-way valve is provided that allows gas to escape but keeps the slurry inside the reaction area of the container.
Another significant problem with known instant self-heating containers is that the heated slurry tends to only contact the bottom of the contents chamber so that the contents at the bottom of the contents chamber are initially much hotter than the contents at the top of the chamber. Where the contents are dispensed from the top of the outer container, this means that the contents that leave the container first are coolest, while the hottest contents remain at the bottom of the contents chamber.
Accordingly, it would be advantageous to provide a temperature changing food and beverage container that has its own long-lasting heat generation source so that the beverage, food, medication, or other products requiring heated or cooled temperatures can be maintained at a relatively constant elevated or depressed temperature for a relatively long duration of time. It would also be advantageous to provide a temperature changing container that can be made from relatively inexpensive, disposable materials.
Another problem with known temperature changing containers is that the exothermic or endothermic reaction occurs all at once. There is a need for a temperature-changing container that allows the user to modulate the chemical reaction over time, thereby enabling the user to control the duration and/or intensity of the reaction.
Finally, another problem with containers for releasing one initially segregated reactant into contact with another reactant is ensuring complete release of the segregated reactant. When initially contained within a chamber sealed by a membrane, known containers generally create a small puncture or tear in the membrane. If this puncture or tear is small, the reactant inside can easily clog the opening and prevent rapid and complete release of the reactant. Accordingly, there is a need for a temperature changing container with an internal segregated reactant that rapidly and completely releases the reactant when desired by a user, that sequesters the reactants, and that provides for efficient heat transfer using conduction and convection.